Rv016 Dmz

I'm working with a client with an RV016...ISP has provided 5 IP addresses, and the router is configured with the first in the block - xxx.xxx.xxx.142 and a /25 bit subnet mask.

A phone company installed a telephone system, and gave me a router to plug in so they could score one of the live IPs for remote access. It's a BEFSR41v4...so I configured it with one of the 5 live addy's, and plugged it into the DMZ port which I setup with another of the 5.

I can ping the RV016 and the DMZ addresses from off-site locations, but not the BEFSR...any suggestions?